Refactor GestureNavigation to eliminate code redundancy

content/browser/web_contents/aura/overscroll_navigation_overlay.h

Index: content/browser/web_contents/aura/overscroll_navigation_overlay.h
diff --git a/content/browser/web_contents/aura/overscroll_navigation_overlay.h b/content/browser/web_contents/aura/overscroll_navigation_overlay.h
index db9871c024981ff908b20bfd9b2ed1baddcc6eaa..d09b85318db815dab4afd38001758d29c51f1217 100644
--- a/content/browser/web_contents/aura/overscroll_navigation_overlay.h
+++ b/content/browser/web_contents/aura/overscroll_navigation_overlay.h
@@ -7,19 +7,17 @@
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
-#include "content/browser/web_contents/aura/window_slider.h"
+#include "content/browser/web_contents/aura/overscroll_window_animation.h"
+#include "content/browser/web_contents/web_contents_view_aura.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
+#include "ui/gfx/image/image.h"
 
 struct ViewHostMsg_UpdateRect_Params;
 
-namespace aura_extra {
-class ImageWindowDelegate;
-}
-
 namespace content {
 
-class ImageLayerDelegate;
+class OverscrollWindowDelegate;
 class OverscrollNavigationOverlayTest;
 
 // When a history navigation is triggered at the end of an overscroll
@@ -29,12 +27,26 @@ class OverscrollNavigationOverlayTest;
 // painting.
 class CONTENT_EXPORT OverscrollNavigationOverlay
     : public WebContentsObserver,
-      public WindowSlider::Delegate {
+      public OverscrollWindowAnimation::Delegate {
  public:
-  explicit OverscrollNavigationOverlay(WebContentsImpl* web_contents);
+  enum NavigationDirection { FORWARD, BACK, NONE };
+
+  OverscrollNavigationOverlay(WebContentsImpl* web_contents,
+                              aura::Window* web_contents_window);
+
   ~OverscrollNavigationOverlay() override;
 
-  bool has_window() const { return !!window_.get(); }
+  // Returns a pointer to the overscroll window animation we own.
+  OverscrollWindowAnimation* owa() { return owa_.get(); }
+
+ private:
+  friend class OverscrollNavigationOverlayTest;
+  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, WithScreenshot);
+  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, WithoutScreenshot);
+  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, CannotNavigate);
+  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest, AbortNavigation);
+  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
+                           AbortAfterSuccessfulNavigation);
 
   // Resets state and starts observing |web_contents_| for page load/paint
   // updates. This function makes sure that the screenshot window is stacked
@@ -44,63 +56,39 @@ class CONTENT_EXPORT OverscrollNavigationOverlay
   // otherwise the overlay may be dismissed prematurely.
   void StartObserving();
 
-  // Sets the screenshot window and the delegate. This takes ownership of
-  // |window|.
-  // Note that aura_extra::ImageWindowDelegate manages its own lifetime, so this
-  // function does not take ownership of |delegate|.
-  void SetOverlayWindow(scoped_ptr<aura::Window> window,
-                        aura_extra::ImageWindowDelegate* delegate);
-
- private:
-  friend class OverscrollNavigationOverlayTest;
-  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
-                           FirstVisuallyNonEmptyPaint_NoImage);
-  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
-                           FirstVisuallyNonEmptyPaint_WithImage);
-  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
-                           LoadUpdateWithoutNonEmptyPaint);
-  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
-                           MultiNavigation_LoadingUpdate);
-  FRIEND_TEST_ALL_PREFIXES(OverscrollNavigationOverlayTest,
-                           MultiNavigation_PaintUpdate);
-
-  enum SlideDirection {
-    SLIDE_UNKNOWN,
-    SLIDE_BACK,
-    SLIDE_FRONT
-  };
-
   // Stop observing the page and start the final overlay fade-out animation if
   // a window-slide isn't in progress and either the page has been painted or
   // the page-load has completed.
   void StopObservingIfDone();
 
-  // Creates a layer to be used for window-slide. |offset| is the offset of the
-  // NavigationEntry for the screenshot image to display.
-  ui::Layer* CreateSlideLayer(int offset);
+  // Creates the overscroll window if it does not exist or a slide window if it

[mfomitchev, 2015/03/26 02:41:39]

It's not clear from this comment what is the "overscroll window" or "slide
window" and these concepts are not established anywhere. Maybe just say it's
created above or below the current top-level window (web_contents or overlay)
depending on the navigation direction.

[Nina, 2015/03/27 17:52:35]

Done.

+  // does and transfers ownership to the owner.
+  scoped_ptr<aura::Window> CreateSlideWindow();
 
-  // Overridden from WindowSlider::Delegate:
-  ui::Layer* CreateBackLayer() override;
-  ui::Layer* CreateFrontLayer() override;
-  void OnWindowSlideCompleting() override;
-  void OnWindowSlideCompleted(scoped_ptr<ui::Layer> layer) override;
-  void OnWindowSlideAborted() override;
-  void OnWindowSliderDestroyed() override;
+  // Returns the screenshot for the given direction.

[mfomitchev, 2015/03/26 02:41:39]

"screenshot for direction" is not clear enough

[Nina, 2015/03/27 17:52:33]

Done.

+  const gfx::Image GetImageForDirection(NavigationDirection direction) const;
+
+  // Overridden from OverscrollWindowAnimation::Delegate:
+  scoped_ptr<aura::Window> CreateFrontWindow() override;
+  scoped_ptr<aura::Window> CreateBackWindow() override;
+  aura::Window* GetTargetWindow() const override;
+  void OnOverscrollCompleting() override;
+  void OnOverscrollCompleted(scoped_ptr<aura::Window> window) override;
+  void OnOverscrollAborted() override;
 
   // Overridden from WebContentsObserver:
   void DidFirstVisuallyNonEmptyPaint() override;
   void DidStopLoading(RenderViewHost* host) override;
 
-  // The WebContents which is being navigated.
+  // The current overscroll direction.
+  NavigationDirection direction_;
+
+  // The web contents that are being navigated.
   WebContentsImpl* web_contents_;
 
-  // The screenshot overlay window.
+  // The overlay window that shows a screenshot during an overscroll gesture.
   scoped_ptr<aura::Window> window_;
 
-  // This is the WindowDelegate of |window_|. The delegate manages its own
-  // lifetime (destroys itself when |window_| is destroyed).
-  aura_extra::ImageWindowDelegate* image_delegate_;
-
   bool loading_complete_;
   bool received_paint_update_;
 
@@ -109,19 +97,11 @@ class CONTENT_EXPORT OverscrollNavigationOverlay
   // when the relevant page loads and paints.
   GURL pending_entry_url_;
 
-  // The |WindowSlider| that allows sliding history layers while the page is
-  // being reloaded.
-  scoped_ptr<WindowSlider> window_slider_;
-
-  // Layer to be used for the final overlay fadeout animation when the overlay
-  // is being dismissed.
-  scoped_ptr<ui::Layer> overlay_dismiss_layer_;
-
-  // The direction of the in-progress slide (if any).
-  SlideDirection slide_direction_;
+  // Manages the overscroll animations.
+  scoped_ptr<OverscrollWindowAnimation> owa_;
 
-  // The LayerDelegate used for the back/front layers during a slide.
-  scoped_ptr<ImageLayerDelegate> layer_delegate_;
+  // The window that hosts the web contents.
+  aura::Window* web_contents_window_;
 
   DISALLOW_COPY_AND_ASSIGN(OverscrollNavigationOverlay);
 };